DNSBL Resource Updates

Last week, at the MAAWG (Messaging Anti-Abuse Working Group) 11th General Meeting held in Arlington, VA, I presented my updated Blacklist Statistics Center. I also gave everyone within earshot a lot of data and a healthy dose of opinion regarding various blacklists, and shared my take on what senders and receivers should consider when measuring the value and reputation of a blacklist.

And, I'm finally fleshing out the blacklist review section of the site. To that end, I've just published reviews of PSBL, FIVETEN, and Spamhaus ZEN. This is to add to the list of ones I've already written (APEWS, SORBS, Spamcop, CBL, Korea and UBL).

I also invented a new blacklist. LUCKYSEVEN isn't suitable for spam filtering, but it helped to put a graphical face on arbitrary spam blocking methodology. Did you know that if you block mail from any IP address containing a 7, you'll block about 50% of spam? Of course, you'll block about 43% of non-spam at the same time, making it just about completely useless. But....still! 50%? Isn't there some value to that? No, not really, but it makes for a neat graph.

Psst...wanna buy a list?

Back in March, Mark Brownlow posted some good info on his Email Marketing Reports site about list rentals, list purchasing, and co-registration.

Is list purchasing a good idea? "With very, very few exceptions, purchasing a bulk list like this is a shortcut to email marketing hell." "No self-respecting list owner is ever going to sell copies of their address list. Not if they want to preserve its value."

Great advice! Click here to read the entire article.

Update: I had missed this new bit of commentary from Mark Brownlow on the same topic, posted just the other day: "
Any list building method not based on gaining an explicit opt-in strikes me as like eating fugu, the Japanese pufferfish dish. It's expensive, not a particularly rewarding experience, and runs the risk of killing you."

Spot on!

Tracking Blacklists

With the latest batch of additions today, I'm now tracking over 50 different blacklist zones for the newly revamped DNSBL Resource Blacklist Statistics Center. Thinking back to when I created the RRSS blacklist (the Radparker Relay Spam Stopper) in 1999, I am not sure there were even fifty anti-spam blacklist filters across the entire globe. Mine was definitely not the first, but I suspect that RRSS was probably one of the first ten.

Right now, I've got 13-week charts showing the effectiveness of 21 different blacklist zones. Look for public stats on additional lists soon, as I slowly compile effectiveness data on the lists I've just added. (And I've got even more tricks up my sleeve, so stay tuned!)

Opt-in Censorship?

As I said to Ken Magill for his recent article regarding Truthout: From what I know of how spam blocking works, and how ISPs make the determination regarding what mail to block, I don't think Truthout's issues (being blocked at Hotmail and AOL) relate to their politics. I think they relate to their opt-in procedures, bounce handling, feedback loops, and whitelisting. The issues are technical, not political.

Getting it Half Right

I'm now utilizing “second stage” filtering, using the primary Spamhaus blacklist, the SBL. For me, it's an experiment. I just wanted to see how well it works and what kind of mail it catches. I know that a large number of email addresses are now behind this kind of filtering – at least one domain registrar (who hosts mail for a zillion different domains) has been using this type of filtering for at least the past few months. So I wanted to see what kind of senders are getting tripped up in this kind of filtering, and how well it works as a spam-blocking methodology.


MailChimp is looking for a few good....monkeys. Ha.